Model Output Discussion - 12th December Onward

[phil nw.]

Interesting on the GFS 12z control run perhaps some sort of hope or sign?

You never know.

T180 on the GEFS thumbs show subtle differences in the movement and ampltude of the High.

I refer to these sometimes in desperate times.They do show what options are available for future evolutions of the zonal pattern.

http://www.meteociel...&mode=1&ech=180

A bit of meridonality in the jet could allow something more interesting down the line.

They are worth a look every so often too see if the trend is taken up by more members as the days go by.

Obviously all output should be considered but these are just sometimes usefull for spotting possible hints of a change.

Edited December 18, 2011 by phil n.warks.

[Pixel]

love this one..

should bring some festive cheer... to Africa (-:

The models are so much fun

[SP1986]

love this one..

should bring some festive cheer... to Africa (-:

The models are so much fun

Is that not just a chart showing the distribution of high and low pressure?

Edit no it isn't - Ive never seen that type of chart before however.

[Swave Snow]

love this one..

should bring some festive cheer... to Africa (-:

The models are so much fun

love this one..

should bring some festive cheer... to Africa (-:

The models are so much fun

I think it is low dew points and high dew points LOL no idea myself

[OldMetMan]

Compare the following chart to the 1947 chart you posted remarkable pressure placements and pressure heights.

Yes it's similar but it still needs amplification of the upper wave pattern, something the 06Z GFS was suggesting but backed off from in the 12Z.

We'll see if that trend comes back in future runs.

[Grimsby Snow Lover]

A little bit of hope thrown up by the ECM this evening, we nearly have regression of the high towards Greenland by 240hrs. Hopefully a new trend?

http://www.wetterzen...cs/Recm2401.gif

Edited December 18, 2011 by Grimsby Snow Lover

[Thundery wintry showers]

In the end, after some "wobbles" regarding the synoptic evolution after this weekend's northerly, those who called a mild Christmas week with the jet displaced northwards look set to be right, after a failed attempt at the same sort of evolution around the 10th December. The mild air will take until Wednesday to get established though, with a front advancing from the west tomorrow bringing mostly rain but possibly some forward edge snow for some, and then another cold snap on Tuesday.

After a polar maritime incursion on the 23rd with a few showers for the north and west, with some of these wintry in Scotland, the Christmas period will most likely end up with a NW-SE split. Most parts of the country look set to be cloudy, mostly dry in the east and wet in the west, but if the high pressure ridges into southern areas as is shown by GFS, then many southern, central and eastern parts of England may see plenty of sunshine, still with daytime temperatures approaching double figures, but also slight frost at night.

[nick sussex]

A little interest right at the end of the ECM run with that more amplifed troughing in the eastern USA.

I'm sure OMM will like this! This could be the beginnings of a change but we shouldn't get too ahead of ourselves, although the ECM has shown very good consistency in its recent runs the interest comes at day 10 but nice to see regardless.

Before then given the solid support it is likely to turn much milder, when you think about it at this stage last winter we were almost at the end of that cold spell, after which the winter was IMO poor, last winter the cooling stratosphere at this stage dealt a blow to snow prospects, at least this is moving in the right direction this time,although it remains to be seen whether we see a SSW but even a minor warming could still make things more interesting.

Edited December 18, 2011 by nick sussex

[Grimsby Snow Lover]

The NAO seems to be improving in terms of returning to neutral values and possible negative values as the year closes out. I have been checking these for well over 3 weeks and todays is the best I have seen. Granted they are no way near as pleasing to the eye as last Decembers, but a big improvement on whats been modelled this season so far, I know they are likely to change like the other models do but something worth keeping an eye on as tonights ECM 240 chart is showing early signs of a blocked Atlantic and possible negative NAO.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

[bluearmy]

the ecm rise in pressure in the atlantic was well trailed by the earlier ens and spreads. whether we get a trough to dig south and introduce some waa at the same time maybe stretching it a bit.

[snowingman]

..........models indicating Nothing on COLD side for at least 2 weeks... any talk of cold on this board is pure finger in the air stuff..

Edited December 18, 2011 by chionomaniac
Removed hypothetical nonsense - You are lucky I have left anything

[bluearmy]

I think it is low dew points and high dew points LOL no idea myself

its an ens spread chart on the heights/thicknesses at T180. the lighter coloured areas show where there is the greatest deviation from the mean. the darker shows where there is less deviation from the mean. looking at that chart, you can see where the azores ridge to our sw is absolutely nailed on whereas to our north, though the mean will show lowish heights, there are many runs which have higher heights in this area, hence the lighter coloured area.

getting very frustrated by the 'winter is over' posts. for gawds sake, its hardly started yet.

Edited December 18, 2011 by bluearmy

[OldMetMan]

A little interest right at the end of the ECM run with that more amplifed troughing in the eastern USA.

I'm sure OMM will like this! This could be the beginnings of a change but we shouldn't get too ahead of ourselves, although the ECM has shown very good consistency in its recent runs the interest comes at day 10 but nice to see regardless.

Yes I do! Let's see if it continues. The UKMet might show a hint of it at T144 later today.

[Cloud 10]

love this one..

should bring some festive cheer... to Africa (-:

The models are so much fun

That chart is a spread of the ensembles,and shows how much agreement there is between the ensembles at a given timeframe.

The dark blue and purple areas show where agreement is good,the yellow areas show where the uncertainty is.

edit.

What BA said!

Edited December 18, 2011 by Cloud 10

[nick sussex]

..........models indicating Nothing on COLD side for at least 2 weeks... any talk of cold on this board is pure finger in the air stuff..

A certain sense of melodrama seems to descend on this thread when the models churn out these types of outputs, let's just wait and see what develops, I've seen output alot worse than this.

Edited December 18, 2011 by chionomaniac
Left important bit

[The Northern Ramper]

..........models indicating Nothing on COLD side for at least 2 weeks... any talk of cold on this board is pure finger in the air stuff.. From years of experience - such a pattern that is building can last weeks and weeks - could we be on our way to a totally snowless winter for most parts?? 50% chance based on these mild charts

50% chance of of a snowless winter for most parts based on tonights charts.

That is wrong in so many ways.

[kold weather]

Ensembles and ECM both suggesting an attempt at a different pattern. The AO lifts from the basement though might still be slightly positive overall. GFS operational one of the more milder runs in the future. Long way to go though and probably a painful pattern to come for the next 2 weeks IMO before things shift, but real hints of something different, though I dobut we get any real northern blocking just yet...

[Tom Montalbano]

As Nick S. states, far too early to get excited over that ECM chart at t240 but this is exactly the sort of evolution I'm hoping will start occurring more and more frequently, in the forecast models as we head towards the end of December.

http://www.wetterzentrale.de/pics/Recm2401.gif

From what seems a dire situation, with high pressure seemingly entrenched to our south, a change in pattern can happen pretty swiftly. With more amplification and the vortex splitting in a favourable position and with help from some WAA out in the Atlantic, more encouraging synoptics could be around the corner. Here are some examples of similar evolutions:

http://www.wetterzentrale.de/pics/archive/ra/1984/Rrea00119841231.gif

http://www.wetterzentrale.de/pics/archive/ra/1985/Rrea00119850101.gif

Jan 1987, was an extremely interesting and complex situation and we needed a few bites of the cherry to hit the jackpot.

http://www.wetterzentrale.de/pics/archive/ra/1987/Rrea00119870102.gif

http://www.wetterzentrale.de/pics/archive/ra/1987/Rrea00119870103.gif

http://www.wetterzentrale.de/pics/archive/ra/1987/Rrea00119870104.gif

http://www.wetterzentrale.de/pics/archive/ra/1987/Rrea00119870106.gif and we all know what happened come Jan 11th.

Just to reiterate, far too early for any excitement, and no we shouldnt get ahead of ourselves but wanted to post these examples to show what can happen from what may seem to be a hopeless situation with strong high pressure cells to our south and an intense PV close to Greenland.

We need to show some patience and there are some encouraging signs elsewhere, i.e the Stratosphere thread.

Some positive signs then starting to appear and Stuart (GP) must be feeling pretty positive at the moment re. his Winter LRF.

This could be a false dawn of course and an Ian Brown type spell is not out of the question, either.

After all, the uncertainty is part of the "buzz" and without it this thread wouldnt be as lively and feisty as it becomes, in the Winter season.

Regards,

Tom.

[phil nw.]

A little interest right at the end of the ECM run with that more amplifed troughing in the eastern USA.

I'm sure OMM will like this! This could be the beginnings of a change but we shouldn't get too ahead of ourselves, although the ECM has shown very good consistency in its recent runs the interest comes at day 10 but nice to see regardless.

Before then given the solid support it is likely to turn much milder, when you think about it at this stage last winter we were almost at the end of that cold spell, after which the winter was IMO poor, last winter the cooling stratosphere at this stage dealt a blow to snow prospects, at least this is moving in the right direction this time,although it remains to be seen whether we see a SSW but even a minor warming could still make things more interesting.

Yes a little teaser with some ridging in the Atlantic on ECM T240.Just a hint that some energy thinks about going south.

However as you say Nick it`s day10 and much to get through first.

I don`t know whether we can get any suggestions of a change on some of the ECM Ens. when they come out.The thumbnails only go out to T168--maybe too soon.

Edited December 18, 2011 by phil n.warks.

[January Snowstorm]

I suppose why many are down about the models is almost everybody sees a white Christmas as a great event

Let's hope GP's forecast comes off and things change considerably in January.

To be fair most lrf's called a mild Christmas so we are still on track for something much better in a few weeks

[nick sussex]

Yes a little teaser with some ridging in the Atlantic on ECM T240.Just a hint that some energy thinks about going south.

However as you say Nick it`s day10 and much to get through first.

I don`t know whether we can get any suggestions of a change on some of the ECM Ens. when they come out.The thumbnails only go out to T168--maybe too soon.

Yes its a shame we don't get to see the upstream pattern with those ensemble maps, although given how stingy ECM are with info I suppose we should be grateful that they release them at all.

The ECM ensembles should at least give us an idea about any ridging in the Atlantic.

The latest ECM ensemble spreads show the main uncertainty is to the west of the UK at 240hrs:

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=1&type=2

Edited December 18, 2011 by nick sussex

[bluearmy]

ecm ens spread at day 10 does show a height rise mid atlantic (not nearly as amplified as the op though you'd expect that) plus a trend to dig the trough to the west of this height rise. whilst not enough support for the op to make it look like the mean, there must be a significant cluster that agree to a reasonable extent.

i also note the 850 spread showing a push sw of very cold uppers towards svaalbard - i assume in association with a chunk of siberian p/v being forced there by the arctic high. thats a solution also shown by the op and therefore, more support for its run.

Edited December 18, 2011 by bluearmy

[Frosty.]

The timing of this upcoming mild spell is unfortunate but it's just the normal peaks and troughs of a british winter, so it looks like being a mild christmas but maybe turning colder towards the new year with luck.

[phil nw.]

ecm ens spread at day 10 does show a height rise mid atlantic (not nearly as amplified as the op though you'd expect that) plus a trend to dig the trough to the west of this height rise. whilst not enough support for the op to make it look like the mean, there must be a significant cluster that agree to a reasonable extent.

i also note the 850 spread showing a push sw of very cold uppers towards svaalbard - i assume in association with a chunk of siberian p/v being forced there by the arctic high. thats a solution also shown by the op and therefore, more support for its run.

Yes hopefully that is some indication that the Azores high may shift out of it`s home ,although i am never quite sure when interpreting the Ens. spreads.

I like to see the thumbnails of the different members for a clear picture.

[leicsnow]

Hmmm GFS doesn't look good for after Christmas.